Extraction of sterols and antioxidants



May 25, 1954 R. M. CHRISTENSON EXTRACTION O STEROLS AND ANTIOXIDANTS Filed Nov. 13, 1951 17T Tof/Vfl( Patented May 25, 1954 UNITED STATES PATENT oFFlcE EXTRACTION F' STEROLS AND ANTIOXIDANTS Roger M. Christenson, Whitefish Bay, Wis., assignor to Pittsburgh Plate Glass Company Application November 13, 1951, Serial No. 256,110

20 Claims. l

derived from a glyceride oil such as soybean oil l0 or related products.

The tocopherols which are anti-oxidants are also called vitamin E. The materials are of interest for nutritional and medicinal uses and a large scale convenient method for their isolation would be of great Value.

It has heretofore been recognized that some of the glyceride oils, notably soybean oil, contain, in addition to a complex mixture of fatty acid triglycerides and free fatty acids, small amounts of unsaponiable compounds such as sterols, tocopherols and other constituents. Many of these unsaponiable constituents were, if recoverable, recognized to be of great value in the preparation of inhibitols or antioxidants for food products or f emulsiers and in some cases, in the preparation of pharmaceuticals such as sex hormones and the like. However, prior to the present invention no suitable process applicable on a large or commercial scale for their preparation has been avail-.30

able. For these reasons some of the materials, although much in demand have remained extremely expensive and the use thereof by the general public has been limited.

The present invention relates to a process whereby the sterols, antioxidants and other unsaponiable constituents of the natural glyceride oils or related products are recoverable economically and in large quantities. According to the process a concentrate of fatty acids or glycerides. and sterols produced according to various methods and containing in excess of 3% by Weight of unsaponiable matter is subjected to the steps of saponifying the fatty acids or the glycerides oi fatty acids associated with the sterols and the antioxidants in soybean oil by means of a suitable alkali, making up the soaps into solution with water and a lower alcohol in such concentration that no emulsions are obtained When contacted with an extracting solvent, then extracting the unsaponiable constituents in counter-current fashion `from the soap solution by application of an appropriate solvent such as naphtha, an ether or a chlorinated hydrocarbon or any other solvent of the unsaponiiiable matter, which ucts comprising soybean oil glycerides or :fattyv acids or soaps of fatty acids or mixtures of these, and unsaponable materials in suiiicient concentration may be employedas starting materials. These may be derived from several sources. For example, in certain processes of extracting oils such as those disclosed in Freeman Patents 2,200,390 and 2,200,391 glyceride oils, such as soybean oil, were subject to treatment with selective polar solvents such as furfural, ethyl aceto acetate or the like, having preferential solvent action to the more unsaturated components of the glyceride oils. The sterols and inhibitols of soybean oil are selectively dissolved by the polar solvent so that the extract fraction resulting from the application of the process is substantially enriched in these components. l

It is usually practicable thus to extract 20 to per cent of the original oil as a solution in a polar solvent such as anhydrous furfural. The solvent can be removed from this solution with the further concentration of the unsaponiflables and the mixture, then saponifed with alkali and treated under the provisions of the present invention to recover unsaponiables. However, in most instances, it is preferable rst to Aselectively remove the major portion of the glyceride oil components from the solution for other uses, at the same time further concentrating the unsaponiable matter With respect to the glyceride oil remaining in solution. Various methods of effect- `ingsuch concentration are available.

Oneconvenient method, however involves selectively extracting the glycerides of the fatty acids from the polar solvent solution by means of a solvent immiscible with or only partially miscible with the polar solvent. Naphtha constitutes one such solvent. Preferably, naphtha o1 paraflinic character is employed and it may comprise hydrocarbons vof various molecular Weights containing, for example, 6 to 10 carbon atoms in the molecule. However, a heptane to decane fraction has been found to operate efficiently in the system. In most instances, it is advisable to strip off a portion of the polar solvent, such as furfural, from the extract solution by distillation before washing the solution with naphtlia.

then to evaporate the naphtha.

Su'icient solvent may be distilled to form a 20 to 50% solution by weight of oil in furiural. The remaining extract solution may then be washed with naphtha within a ratio of approximately .2 to 10 parts by volume per part of original oil extracted. The operation may be conducted countercurrently ina suitable column .or may be conducted batchwise. Preferably, the temperature of operation is within an approximate range of 45 to 95 F. though variations of iive or ten degrees higher or lower are contemplated.

As a result of the washing of the 'extractsolution of oil dissolved in polar solvents, nearly all of the glyceride oils are extracted out into the naphtha solution. The naphtha from this -solution may be evaporated and the oil recovered for use as a drying oil or for other purposes. There remains in the polar solvent a concentration of the free fatty acids andthe unsaponiiiable mattei' and some glyceride oils. This latter portion,

Yhereinafter called by-product, is small with respect to the Aoriginal oil extracted but is, 'oi

course, considerable with respect to the small amount of unsaponiiiable matter. The 'free fatty acids, unsaponiables and glyceride 4`oils may be recovered from the polar solvent solutionby evaporation of the solvent. It is also permissible to extract them out with an excess of "naphtha and The composition of the recovered portion is approximately as follows:

I `5 to 40 percent by weight free `fatty acid 4 to 30 percent by weight unsaponiable matter The remainderglyceride oils and other lconstituents If preferred, a concentrate of the unsaponifiable matter, free fatty acids and a vsmall amount of glycerideoilmaybe recovered from an extract `product oil by contacting this extract oil with a i wet polar solvent, :such as fa saturated or nearly saturated solution of furfura'l and water. :Conf veniently, this extraction can be conducted at Va 'temperature of about 60 to 90 F. Before the aqueous furfural extraction, all or much of the original polar solvent, such as furfural, employed "in initially treating the original oil,may be elimf inated -by distillation.'

Asa result ofthe e. traction ofthe original extract oil with wet polar solvents such as furfural, the free 'fatty acids, unsaponifiable matter and a small amount of glycerides Aare lextracted in the wet solvent. The glycerides'of the free iatty'acids are relatively insoluble vand separate 'out 'as la layer which can be recovered for other purposes. The remaining concentrate or by-product oi unsaponiable matter, free fatty acids and residual glyceride oils `or glycerides of free fatty acids may be recovered by evaporation of the solvents and-are of .much the same composition 4as that.'I

recovered by the Aextraction vof the polar vsolvent extract with'naphtha.

Another appropriate source material 'of kunsaponifiable matter suitable for use in the practice of the present invention comprises the so-.

called soap stocks and roots acids resulting from the reiining of soya oil with small amounts of alkali. In this reiining operation, small amountsof free fatty acids and glycerides of soya oil 4are converted into soaps, and when these are separatedioif, it has been found that a high percentage of the unsaponifiable matter and notably of thesterols, of which stigmasterol is one of the most important, are retained Ain the soap fstock fraction. Soap stocks also include considerable amounts of unsaponiiled glycerides as well as substantial amounts of water. A typical composition of a soya soap stock is given on page 834 in the book Soybeans and Soybean Products, volume II, by Klare S. Markley. When recovered, the free fatty acids liberated are of considerable value.

i 'sapon-.ifiable matter exists in the alcohol layer.

3. 'The distillate Tfrom the molecular distillation of soybean oil.

4. In the treatment of soya oil with adsorbants f suoli as fullers `earth or activated clay, unsaponf iable matter is selectively adsorbed and the re- :sultant concentrate of unsaponifiable matter can be extracted out from the adsorbant, after the latter has been filtered o, by treating Vthe ad- :sorbant `with naphtha or other solvents. When the naphtha is evaporated, the concentrate `is recovered.

5. A Iconcentrate of unsaponiiiable matter is :obtained by liquid extraction of soya oil with a lower aliphatic alcohol of one to three carbon atoms such as methanol, ethanol, propanol or isopropanol.

6. 'Concentrates o'f unsaponiilable matter distill oir when the soya oil is vacuum deodorized by blowing with steam.

7. Fatty acids from saponification and subse- =quent acidification of soya oil or by hydrolysis of soya oil, or soya soap stocks may be extracted, -for example, with furfural and naphtha, as 4disclosed in my application Serial No. 160,919, filed May 9, V1950, now Patent 2,573,891, to provide a concentrate very rich in unsaponiable matter.

8. A concentrate of unsaponable matter prepared by the extraction of soya oil with liquid propane.

Allof vthese materials containing about 3% and Vupward of unsaponifiables can be employed as starting materials in the practice of this lnvention. The concentrates can be saponied with alkali, made up into an appropriate solution in water and a lower water soluble, monohydric 4alcohol and then they can be countercurrently extracted with naphtha or other sol- -vent of unsaponiflable matter which is at least -be `effected by saponifying the concentrate with `alkali and then acidifying the resultant soaps.

The acids can also be liberated by hydrolization `or by 'Twitchellization or simlar methods. A

.large amount of `the lfatty lacids can then be distilled. .As a result of vthis operation, the unsaponilable matter, land notably the sterols, are

3-50% by weight unsaponiable matter 570% by weight of free fatty acids or soaps The remainder-glyceride oils and other constituents 'I'hese compounds are saponifed and the saponified mixture comprises in addition to water and alkali, the following:

5-35% of soybean oil concentrate (in a saponifed form) 10-40% of methanol, ethanol, isopropanol, or

propanol 30-85% water 0.5-7.0 of alkali (as soaps or free) Extraction of an alcohol solution of such a saponiiied mixture with naphtha or like solvent may be eifected in an apparatus such as an extraction column of the type disclosed in the present drawings. It may also be eifected by continuously feeding naphtha and soap solution into a centrifuge of the so-called Podbieniak type. The solution in the latter is fed in at the axis and naphtha in at the outer periphery. The denser component (soap solution) permeates outwardly along an involutely coiled perforated diaphragm in the centrifuge and the naphtha permeates inwardly in kcontinuous countercurrent ilow. 'I'he naphtha phase is drawn off at the axis of the centrifuge and the soap solution is drawn off at the periphery. This type of apparatus is covered in patents such as: 2,209,577, 2,281,796, 2,109,375, 1,936,523, 2,286,157.

A suitable embodiment of apparatus for use in the practice of the invention is illustrated in the drawings and comprises columns I and II. A soap solution of unsaponiiable concentrate may be fed into column I near the top thereof as indicated at 3 and a naphtha solution is fed in near the bottom as indicated at Il. Soap solution from which the extract matter has been removed is drawn off from the bottom of the column as indicated at 5 and passes to a still 6 for removal of the solvents contained therein. The soaps may then pass through a line 1 to a container 8 where the soaps are acidied in order to regenerate the free fatty acids. Such acids are drawn off as indicated at 9 and passed to a container I6 for storage or for further treatment.

The solution of unsaponiable matter in naphtha is drawn off at the top of column I as indicated at il and passes to a zone slightly above the bottom of column II. Simultaneously, water is fed into the top of column II as indicated at I2 in order to wash out residual soaps from the concentrate of unsaponiflable mater. The naphtha solution of concentrate is drawn off as indicated at I3 at the top of column II. Simultaneously, the water solution of soaps and other water soluble constituents is drawn off as indicated at i4, and may be subjected to further treatment. The naphtha solution of unsaponiable matter passing out at I3 may be subjected to further treatment, for example to evaporation of unsaponiable 6.. in order to eliminate the naphtha contained therein.

The proportioning of the several components in the centrifuge or in the column I will vary to some degree for different alcohols as solvents.

e. g. methyl, propyl alcohol, the proportions usually will fall approximately within the ranges specified in the examples which are to follow. In most instances,

the proportions in the solutions comprising water., and an alcohol of l to 3 carbon atoms may vary.

A good average statement of proportions in the nal feed solution for any of these alcohols will be approximately as follows:

Saponied sterol concentrate, parts by weight upon a water free basis Water, 146 to 1460 parts by weight Alcohol of 1 to 3 carbon atoms, 6l to 610 parts by Weight Naphtha preferably is employed in a ratio of 1 to 10 parts by volume per part of soap solution.

The temperature of operation of the system may be almost any from approximately normal room temperature or thereabouts up to that at which one or more components of the system tend strongly to volatilize off.

The temperature should not exceed the boiling point of any component of the system. A range of about 100 to 160 or 180 F. is preferred.

The liow of solvent of iinate and the extract, and the phases will eifectively separate from each other in the clearing ends of the column.

If desired, the naphtha solution of unsaponisaponiable matter.

The concentrates of free fatty acids and unsaponiable matter in the small residue of glyceride oil is excellently adapted for treatment in accordance with the provisions of the present inventlon for purposes of recovering the sterols, tocopherols and other unsaponilable constituents. In order to accomplish this result the free fatty acids and the glycerides are first converted into soaps soluble in water and alcohol.

The following examples illustrate the applica-v tion of the principles of the vinvention in the recovery of unsaponiable matter of soybean oil from a concentrate such as is herein described.

Example I 2go-vasca partei methyl alcohol. The totallwater was 3065. liters or 306-1 kilos. The total methyl alcohol was 1639ekilos=or 2060-1iters; l-t is contemplated that substantial variations in these values may at tiniesbe desired. Proportions of as low as 50% orasfhigh. assour or live-:toldV are contemplated. Thisvariation may be tabulated as follows:

By-product oil as soa-ps, 100 parts by weight upon a water free basis Water, 153-.5' to 1535 parts by weight Methyl alcohol, 81.9 to 8119 parts by weight Column temperature, 148 F. Soap` solution: feed; Naphtha feed, l2()l parts by volume per minute From the original 1000 kilograms ofv extract were recovered 4.2`kilograrns, of unsaponiiiable matter relatively rich in stigmasterol. Recovery of the unsaponiable matter may be attained by evaporation of solvent or other appropriate method.

Example' I Il Two hundred pounds of extracted soybean oil by-product of the same character as that described in Example Ibut containing more unsaponiable matten, was saponied with 50 pounds of sodium hydroxide in pounds oi water and 185 pounds of isopropyl alcohol under reux. This solution was diluted with 530 pounds of water and extracted in the countercurrent column with a heptane fraction of naphtha. The total amount of water was 555 pounds and the total' amount of isopropyl alcohol was 185 pounds. Assuming' a variation of 50 to 500 per cent of these values, the range of proportions for the several components of the system may be tabulated as follows:

Parts by weight By-product oilassoaps 100 Water 138.8 to. 1388 isopropyl alcohol 45.2 to 462 The solution, like that disclosed in Example I, is particularly wellv adapted to countercurrent extraction because it does not emulsify in such operation- The conditions oi operation were as follows:

Column temperature, 106 to 125 F. Soap solution feed, 135 parts by volume Naphtha feed, 405 parts by volume The resultant naphtha concentrate of unsaponiable matter was then further washed in a second column` with Water in order to remove any residual soaps remaining in solution in the naphtha. The second column was operated at a temperature of 96 to 148 F.

1nv this manner 12.9 pounds or 5.45 per cent of unsaponiflable matter based upon the extract treated was recovered upon evaporation of the solvent. Thisi unsaponiablematter representedf 93.4 per cent of the tocopherol and 98.4 per cent of. the total. sterol content of the concentrate which was subjected tov saponification.

65' parts by volume perminute ceptible of considerable variation.

Inmalz'rng up the soapesolutonsfor. extraetion of the.- unsaponiable matter irrExamples I and Il', wideV` variations in the ratiosr of` the water and alcohol components?- to the` saponied concentrate are contemplated. The total. ofone or both; of these components may be 50% orfeven less than given in the examples.. Onl the other hand, theratio or either. or bothothesa components may be. increasediour or five foldfor even more.

The alkali employed in saponiilcationsY maybe nearly molar with respectI to the. total ofthe fatty acids presentas' free acids orcornbined as triglycerides of theAV acids but the ratio is sus- For example, the ratio may befas-rnucrr,asi100% greater. than molar. Usually, undue: excesses are uneconomical.

As a preliminary of the saponication and exltraction of the soybean oil concentrate. of unsaponiflable matter as. obtained from furfural or other polar solvent extraction of soybean oil, the concentrate may be subjected to treatment in order to facilitate the elimination of coloring matter in the unsaponiable matter. In this operation the by-product: or'. extracty beforez it; is saponied; is treated'. with 22 pounds' of. commercial suliul'ici'acid disso'lyedrin'` 22` pounds; oi' water per each '200: pounds'. oli oil'. The? mixiture is thoroughly agitated for.' severalhours: at a temperature of approximately "A F. The suliuric acid' may then vbe.` allowed to separateaand dravm off and the. resultanttreated oil or icy-product oil is Washedtwith water or, ir preferred, the sulfuric acid may be left in they oil and neutralized with alkali',V such asi sodium hydroxide: Whent the: by-product. oil is: thus treated with sulfuric acid. and. subjecteditosaponication and extractiorrinaccordance with' the provisions ofthe present4 invention;- iti found that fcertain objectionable coloring matter: initially prescntrin the by-product is retained; preferentially 'in' the soap solution and isf not" extracted*` out. into the naphtha concentrate oi; unsaponia'ble matter.

It will be appreciated. that in the foregoing examples and in similar.' applicationsor theprinciples' of the'4 invention. sodium hydroxide-,- po'- tassium hydroxide,y orl ammonia or amines may be. employed, in .the performance of; the saponication operation. Methyl alcohol or` ispropyl alcoholA may 'be replaced: by other of. the lower: aleoholsV such: as@ ethyl, orn-propyl alcohol. Naphtha may be replaced by an ether such as diethyl ether or `other' ethers` or byv aromatic hydrocarbonsV such as. toluene or. xylene or by halogenated hydrocarbons suchas ethylene dichloride or indeedr by any' other? liquid organic solvents which are substantially immiscible witl'rthc alcohol and' water solution of soaps and unsaponifiable matter.

In the extraction of the-soap solution in order to remove the unsaponiable matter, the ratio of solvent to soap solution is susceptible of' wide Variation. though` it is .preferable that the solvent should at least equal the volume of the soap solution. Howeven. any ratio of solvent to soap solution above this value can be employed. Of course, excessive. increase, of the volume of solvent becomes uneconomical because, of' the amount of solvent required to be evaporated and because of the size of the apparatus in` proportion tothe amount of material treated. Probably itk will seldom. be. desired to employ a higher ratio solvent for unsaponiabl'e matter than 10 parts by volume to 1 part by volume of soap solution.

Example III In accordance with the provisions of this example, a concentrate rich in tocopherol, sterols and other unsaponiable matter of soybean oil was obtained from a by-product fraction of soybean oil resulting from extraction of soybean oil with a polar solvent as disclosed in Freeman Patents 2,200,390, 2,200,391 or 2,539,661, or Freeman applications Serial No. 62,089, led November 26, 1951, now Patent 2,573,910, Serial No. 34,453, filed June 22, 1948, now Patent 2,573,898, Serial No. 608,119, led August 1, 1945, now Patent 2,573,896, and subsequent extraction of the major portion of the fatty acid glycerides from the polar solvent phase with naphtha. The by-product portion rich in fatty acids, tocopherol, sterols and other unsaponiable matter is retained in the polar solvent phase, and was recovered by distillation of the polar solvent.

In accordance with this such soybean by-product of an acid value of 32, and iodine value of 137.9, a 2.51% tocopherol and 7.89% unsaponilable matter, was treated with caustic soda in such manner as to minimize destruction of tocopherol. A satisfactory procedure involved addition of 20 pounds of sodium hydroxide, 69 pounds of Water, and 125 pounds of 100% isopropanol to the foregoing quantity of by-product. Preferably the mixture of sodium hydroxide, water and isopropyl alcohol were refluxed together prior to the addition of the byproduct, in which might adversely eifect the tocopherol content of the by-product. Manifestly, if tocopherol is not to be recovered along with the other unsaponiable matter, the refluxing procedure may be eliminated. The mixture was cooled to about 50 C. while nitrogen gas was bubbled through it, at which point the by-product was added and the mixture was refluxed while being protected with nitrogen, until saponication was complete or substantially complete. To this saponifed mixture, 186 pounds of oxygen free Water was added to provide a feed solution for the column I. Care Was observed at all stages to avoid admission of oxygen to the solution. This can be attained by maintenance of a blanket of nitrogen gas over all free surfaces of the solution at all stages.

The feed solution as obtained, was of the following composition:

example, 100 pounds of Per cent by Weight By-product (as soaps) 20 Isopropyl alcohol 25 Sodium hydroxide (free and combined) 4 Water l Such mixture contained 0.50% tocopherol and 1.581% of unsaponiable matter. The specific gravity of the mixture was 0.974.

The solution of soaps and unsaponiable matter was fed in at 3 into the upper portion of the extraction zone in column I, which in this instance was a stainless steel tube of 2 inches diameter with an inlet for solvent of unsaponiable matter spaced 59 feet below the inlet for the soap solution. There was a 20 foot clearing section at the top of the column and a 5 foot clearing section at the bottom. The column was operated at a temperature range of 130 F. to 140 F.

In a first run, column I was fed at 3 with 50 cc. per minute of soap solutiony and at 4 with a naphtha Without any alcohol, at a rate of 150 cc. per minute. With naphtha alone as solvent meorcler to eliminate dissolved oxygen 10 dium for the unsaponiable matter, difficulty of operation was experienced at these rates, owing to some emulsication of the phases with each other in their passage through the column.

In a second run, the substitution for the naphtha alone, of a naphtha feed, containing 4.76% by volume of isopropanol upon the basis of the mixture of solvents, eliminated the diiculty from emulsication and ready separation of phases was attained.

Runs were made to ascertain the maximum rate of feed in the above described column and under the conditions of operation previously described. The feed of soap solution in the last preceding example was increased in stages rst to 60, then 70, then 80, then 90, and finally to cc. per minute, the feeds of naphtha and isopropanol being increased proportionally. No difliculty with column flooding was experienced at any of these rates. These constitute excellent rates of feed.

The naphtha solutions of unsaponiiable matter from column I were Washed with Water in column 1I which was of iron and of similar diameter to column I. The temperature of Washing ranged from F. to 110 F. The spacing of the inlets for wash Water and naphtha solution of unsaponifiable matter in column II was 471A; feet. Clearing sections respectively of 1% feet and 2 feet were maintained at the top and bottom ofthe column II. The wash water feed was in a ratio of 1 to 1 with respect to the original Water-alcoholsoap feed to column I.

The recovery of available tocopherol based on the content of the original by-product was 80%. The recovery of unsaponifiable matter Was 99% upon the same basis. (Percentages as herein given are by Weight.)

Recovery of a fraction of increased tocopherol content from the recovered unsaponiable matter may be effected in various ways. For example, the unsaponiable fraction from column II may be subjected to distillation to eliminate the naphtha. The mixture of tocopherol and other unsaponiable matter may then be subjected to vacuum distillation preferably accompanied by hydrogenation in order to obtain a fraction of high tocopherol content. The sterols may be removed from the distillates by crystallization from solvents.

On the other hand, the unsaponiable material may be subjected to fractional crystallization from a medium such as a mixture of 68% by volume methanol and 32% by volume of isopropyl ether. The ratio of solvent to unsaponiable material upon a Weight basis may be 4 to 1. The rate of solution of the unsaponiable matter may be promoted by refluxing the mixture. A sterol rich fraction may be crystallized off at a temperature of 10 to 15 C. The crystals so obtained are Washed with solvent to remove the intense color(yellowred) and the sterols remaining are of straw color. They may be subjected to any further processing which may be desired.

The solution of inhibitols comprising tocopherol remaining is of intense red color. It can be processed further by distillation or hydrogenation if so desired.

Example IV In this example, the starting material was again a by-product recovered from the furfural after extraction of the major portion of the glycerides from the furfural with naphtha in Diameter 6inches.

Height v8&75 feet.

Upper clearing zone 3;'75 feet (unpacked) plus 131.75 feet packed.

Lower clearing zone- 6 feet v(unpacked).

The temperature ranges corresponded to those disclosed in Example III.

The feed rate was:

Soap solution 150'milliliters per minute. The naphtha feed was varied from 15,0 to 600 nulliliters per minute, milliliters per minute. Thel isopropyl content of the naphtha employed for .extraction Variedfrom 2.44% to 4.76% byvolurne.

The naphtha extract solution was washed in column II which was ,packed in the extraction zone with 1/2 inch Berl saddles and which was of the following dimensions:

Diameter 3 inches.

Height I f 87 feet, 6 inches.

Upper clearingzone- -22\feet, 10 inches (packed).

Lower clearing zone 6 feet,.6 inches (unpacked).

A. total of 1780-pounds'of by-product were so processed. A yield o f 1,2 2 pounds of unsaponifiable matter, representing a percentageyield of 97% of the available unsaponiiiable matter, was

recovered. This contained 33.7 pounds or 31.7% v

of tocopherol.

About pounds of the unsaponiable matter .was crystallized at 209i C. from a mixture of 70% by weight methanol. by Weight iSOPlQPi'l ether. The crystals were washed solvent. A yield of 29.5% based upon the unsaponifiables of sterols having a melting point of 1373-1382? C. was obtained.

The inhibitol fraction was retained in the solvent. rIhe inhibitol constituted 4,83% on the basis of the original by-product. The tocopherol content was 1.93% on a like basis.

The following additional examples illustrate the application of the techniques of thepresent invention to the recovery of unsaponiable matter, and notably of streols, from thesoap stocks from soya oil. It is preferred to split off the fatty acids combined with glycerides as free fatty acids and then to distill off a considerable proportion of such acids as an intermediate step. In some cases, the stocks may contain considerable amounts ofgum which may interfere with the splitting operations. gum may be removed, in accordance with the provisions of the present invention by preliminarily treating the stock With 15% sulphuric acid and Washing out Water soluble materials with Water.

yIn any event, the final fatty acidmixture containing the unsaponiable matter, before distillation, will contain from approximately 3 to the average being about 300 with additional `10% of unsaponiablefmatter, and l80 to97% of free acids. Residual esters may also be present. rIhe percentage of the latter may vary from 0 to 10%. The percentages, Aas above given, are to be considered as being b y Weight. The mixtures may be distilled under vacuum, and the temperature-should `not be permitted to go substantially above 250 C. In this manner, a dis.- tillate constituting 75 to 95% of ythe chargezcan be obtained. .Small amounts 4of unsaponiflable matter may also be present the distillate. The amount will usually be within the range of 101.5 to 2% by Weight. Normally, but little of the sterols will be carried over into the distillate.

The pot residue is a dark viscous liquidoreven a semi-solid or waxy material. The pot-residue will contain, in most instances, about 5 to 50% unsaponiiable matter including nearly all of the sterols and from 5 to 60% volatile fatty vacids and polymerized fatty acids, and any glycerol esters resulting from incomplete splitting, and Yany Wax-type esters from the sterols and other alcohols in the unsaponifiable matter. Soya acid distillation pitches generally will contain at least 20% unsaponiable matter, of which about 50% comprisesthe sterols, which are rich in stigmasterol.

AThe sterols from the distillation residues .cannot be recovered by direct methods, -such as crystallization, probably because most .of the sterols are tied up in the mixture inthe form of esters. The saponication operations herein disclosed result in splitting of these esters and the subsequent steps of solvent extraction of the unsaponifiable matter .eliminate the fatty acids as soaps from the system so that the sterols can then be separated off in relatively pure state by crystallization, or vby distillation under high vacuum, or by other methods.

It is to be understood that approximately a seven-fold increase in the concentration of the sterols is secured by distillation. The pot residue or still residue Will contain from 4 to 8 times as much sterol as the Whole fatty acid feed stock which is subjected originally to distillation.

YIt must be recognized that distillation Vcondi-- tions rmay influence yield and properties of the sterols in the distillationresidue. Temperatures that are too high, or too long an exposure to more moderate temperatures may cause destruction or deterioration of the sterols. Distillation should be conducted under vacuum and at a relatively low temperature, and at as high vacuum as is practicable to attain, is preferred.

An appropriate solution system obtained from a distillation-pitch from a soya soap stock acids comprises a mixture of distillation pitch in the form of soaps and unsaponiable matter, 20% .by Weight; isopropanol, 25% by weight, sodium hydroxide, partially in the form of soaps, 4% `by weight; and the rest (51% by Weight) water.

In the saponication of the glycerides and the free fatty acids of a soap stock, a by-product 'from solvent fractionation, or similar source material containing relatively large amounts of unsaponiable matter, alkali such as sodium hydroxide or Apotassium, hydroxide preferably, is employed suiicient excess to .insure complete saponiiication. Usually the excess proportion will not be greater than-l00% upon a molar basis.

The `following examples illustrate the application of the invention to the separation of unsaponiable-matter from a soap stock obtainedin the refining of. soya oil with alkali..

Eample V G3-39 of the American Oil Chemists Society and was found to contain 52.8% fatty acid. The remainder consisted of water and Water soluble constituents. The fatty acids were found to conunsaponiable matter.

into solution with 4,000 grams of water and 2,660 grams of isopropyl alcohol. The solution was fed in a continuous stream into the top of a 1 inch laboratory column, 6 feet long, appropriately packed with 1A; inch Berl saddles. The clearing zones were approximately 0.5 foot foot bottom.

by evaporation of the naphtha. This constituted a yield of 87.9% of the unsaponiable matter present in the original sample. separate sterols rich per part by weight of the unsaponiable matter. Upon cooling the solution, the sterols separated out and were iiltered. The sterols were obtained as a crystalline product having a melting point of 130 to 132 C. with a yield of 17.0 grams.

A distillation pitch as obtained by distilling a mixture of soybean acids and soybean unsaponilable matter from a soap stock as obtained in the rening of soya oil may be substituted for the undistilled material as described in the foregoing example. mately to 30% by weight of unsaponiable matter. Sterols having a melting point of 127 C. can readily be crystallized out in a yield of upon the basis of the unsaponiable matter.

Example VI In this example, a distillation pitch from a commercial soap stock obtained in the rening of soybean oil was employed as a starting material. This pitch contained 20.5 per cent by weight of unsaponiable matter. The remainder of the pitch was primarily fatty acids of soybean oil. For purposes of saponication, a batch was made up as follows:

100 parts by weight of pitch 15.0 parts by weight of alkali 55.5 parts by weight of isopropanol 52.5 parts by weight of Water This batch was renuxed for 8 hours in order to attain relatively complete saponication. The resultant mixture was then diluted so that the solution to be extracted with solvent of un- Such pitch contains approxir saponiable matter had the following compostion:

Pitch (as soaps) 19.1 Sodium hydroxide 2.9 Isopropanol 25.6 Water 52.4

The resultant solution was subjected to countercurrent extraction with naphtha of approximately heptane grade.

Run 1.-In this run, an iron column of 2 inches diameter packed with 1/2 inch Berl saddles was employed as column I. The column was 51 feet tall, there being a 1.75 foot clearing zone a at the top and a 2 foot clearing zone b at the bottom. The wash column II was also 51 feet tall and was constructed of iron. The upper clearing zone was 1.75 feet (unpacked) and the lower clearing zone was 7 feet, of which 5 feet were packed.

Soap solution was fed into the top of the column at a rate of 40 milliliters per minute and naphtha containing 4.76 per cent by volume of isopropanol was fed in at the bottom at the rate of 60 milliliters per minute. The temperature of the column was 145 F. at the top and 135 F. at the bottom.

The naphtha extract solution from the column I was fed into the column II at a rate of 70 milliliters per minute and was Washed with an equal volume of a mixture of per cent water and 20 per cent isopropanol. (Percentages are by volume.) The temperature of the column was F. at the bottom and 143.5 F. at the top.

Run .ZX-In this run, a stainless steel column of 6 inches diameter was employed for purposes of counter-current extraction of the soap solution with naphtha. The column was packed with 1/2 inch Berl saddles, was 88 feet, 9 inches tall with a space of 79 feet between the inlet for soap solution and the inlet for naphtha solution. A 3 foot, 9 inch unpacked clearing zone was left at the top and a 6 foot unpacked lower clearing zone was left at the bottom of the column. The soap solution was fed at 3 to the column at a rate of 300 milliliters per minute while naphtha of an average of 7 carbon atoms per molecule was fed in at 4 at a rate of 600 milliliters per minute. The operating temperature was F. at the top and F. at the bottom. f

The naphtha extract solution containing a concentrate of unsaponiable matter of the pitch, was washed in a stainless steel column of 3 inches diameter, 65 feet high packed with l@ inch Berl saddles. The inlet for naphtha solution was 6 feet, 6 inches above the bottom and the inlet for washing uid was 55 feet from the bottom. The top clearing zone was packed. The bottom clearing zone was unpacked. Wash Water was fed in at a rate of 250 milliliters per minute. The naphtha extract solution was fed into the 3 inch column as it was taken 01T from the 6 inch column. The 3 inch column was operated at a temperature of 125 F. bottom and 130 F. bottom.

In both of these runs, at least 95% of the unsaponifiable matter in the soap solution was extracted. The unsaponiable matter obtained by evaporation of solvent was a brownish solid.

For purposes of purification yo1 sterols, the unsaponiable matter was dissolved in a proportion of 1 part by weight in 10 parts by weight of a mixture comprising 30 per cent by weight of isopropyl ether and methanol. In order to obtain solution of the 70 per cent by weight of canarios solids, ithezsolvent:Waszrefluxedtrandzheiresultamt mixture was filtered while hot to removeany suspended matters'contained therein. The solution was .cooled to 29 C. .and the :cropwof Vcrystals which came .down wasflltered orf, washed `and dried The product had .a somewhat Abrownish color but themelting .point was within the yrange of 134 to 135 C. The yield was 49.7 per cent of the unsaponiable matter, or 10.3 per cent based upon the original pitch. The color of the crystals could be improved by recrystallization and/or treatment of the solution thereof with activated carbon. 1n many instances, such decolorization treatment apparently would not 'be required.

The extracted soap .solution obtained in the foregoing treatment was .acidied and the free fatty acid layer was water washed and dried. The fatty acids were then distilled under vacuum to yield 58.7 per cent'by weight of distilled acids of an iodine value of 95.1, acid value .of 193.7. 'The product was a semi-solid atroom temperature.

Example `VII Substitute methyl alcohol for isopropyl-alcohol in any one of the preceding'examples and proceed as outlined in the example.

Example VIII Substitute ethyl .alcohol for isopropyl alcohol in any `of Examples I through VI and proceed as outlined in the selectedexample.

Example IX Substitute propyl'alcohol for 'isopropyl alcohol in any one of Examples I through Vland proceed as outlined in that example.

The forms of the invention herein described are to be regarded merely as by way of example. t.

It will be apparent to those skilled in the art that numerous 4modifications may be made therein without departure from the spirit of the invention or the scope of the appended claims.

rThis application is a ycontinuation-impart of my copending 4applications Serial YNumbers 160.,- 919 filed May -9, 1950, now Patent 2,573,891, and 162,269 led May 16, 1950, :now cabandoned.

I claim:

1. A process yof obtaining a concentrate .of the unsaponiable matter of soybean oil from a mixture of fatty glycerides Aoi `soybean Voil vcontaining from 4 to 30% of unsaponiable `matter of soybean oil and 5 to '40% of free fatty acids .of soybean oil, which process comprises saponifying the glycerides and the free fatty acids said mixture with an alkali, making up the resultant mixture containing 4soaps of free fatty acids and unsaponifiable matter into solution with water and isopropyl alcohol, the water being present ina proportion of 277.5 to 2775 parts, and the isopropyl alcohol being present in a proportion of 92.5 to 925 parts-for each 200 lparts of the mixture, then removing the nnsaponiable matter from the `mixture by introducing the solution into the upper portion of an extract-ion zone while introducing naphtha, .in a proportion of 1 to 10 parts per part of solution, into the lower portion of the same zone, drawing oir the naphtha ,solution of unsaponifiable matter atthe top of the zone, and evaporating the naphtha to .obtain said fraction of unsaponifiable matter.

2. A process of obtaining a concentrate of unsaponiable matter, comprising sterols and inhibitols, from a'rnixture thereof `resulting from the solvent extraction of` soybean voil witnfurfural to obtain a solution :of highly unsaturated glycerides, sterols, inhibitols, and free fatty acids in furfural, extracting Vout most of the 'glycerides from the-solution with naph'tha, and evaporating the furfural in lthe residual solution, which process comprises "the steps 7of saponifying the residual glycerides and free fatty acids 'fromthe Iurf'ural solution with sodium hydroxide making up the soaps vand unsaponifiable matter as a solution in water Aand isopropylalcohol, the `isopropyl alcohol being employed in a proportion of 185 pounds 'for each '290 Apounds 4of the -concentrate prior to sapcniilcation, the solution being diluted with 555 pounds of water, the unsaponifiable matter being extracted 'outof the solution counter-currently by introducing `the solution into the upper portion of 'an extractionzone and introducing naphtha into the lower portion of `the same zone, allowing the solution and naphtha to flow ycounter-currently `with vrespect to each other, recovering Athe naphtha solution of 11nsaponinable matter at the top 'of the extraction zone, land evaporating the naphtha.

'3. A process of obtaining a concentrate of the unsaponiable matter of soybean oil from a mixture of fatty glycerides, unsaponiable matter and free fatty acids of soybean oil obtained as a by-product by .extracting soybean oil with furura'l and washing the i'urfural solution, rich in vunsaturated glycerides and unsaponiable matter, withnaphtha to remove glycerides, recovering said by-product from which process comprises saponfyingithe free fatty acids and the glycerides of the by-product with sodium hydroxide, and making up the resultant .ixture of soaps of fatty acids of soybean oil and unsaponii-lable matter of soybean oil .into solution in a mixture of water and an alcohol of a class consisting of isopropyl alcohol .and methyl alcohol.; for isopropyl alcohol, for each parts by weight upon a water free 'basis of the byproduct subjected to saponication, 46.2 to 462 parts by weight of isopropyl-alcohol and 138.8 to 1388 parts by weight of water; for methyl alcohol, for each 100 partsof by-product, the proportionseofmethyl'alcohol being 81.9 to819 parts, and water v153;() to .115301'0 parts; `and the alcohol solution vthen being lextracted with naphtha in a proportion of 1 to 10 :parts :per part of solution extracted, then vseparating the naphtha solution of unsaponifiable matter from the water and alcohol solution of soaps, and evaporating the naphtha to recover the unsaponiable matter contained therein.

4. A process as defined in claim 3 in which the alcohol is methyl alcohol.

, 5. Aprocess of .obtaining a concentrate of unsap'onifia'ble matter .of soybean oil, which process comprises contacting soybean oil containing unsaponiable `matter and free 'fatty acids, with furfural to extract 'out `a :fraction or" said oil rich in more highly unsaturated glycerides, free fatty acids land unsaponiable matter, and contacting the resul-tant solution with Anaphtha selectively to extract out the major portionof theglycerides from the furfural, evaporating the furfural from the remaining 'solution of by-product, then saponifying the free atty'a'cids and the glycerides from the `llay-product, with sodium hydroxide, making up the resulta-nt mixture comprising soaps of fatty acids of Vsoybean oil and unsaponfiable matter of soybean oil into solution vin a mixture of waterland an alcohol oi' aA class consisting vof isopropyl alcohol land lmethyl alcohol; the solution 'for isopropyl alcohol comprising, 'for each 100 parts by weight upon a Water free basis of the by-product subjectedl to psaponication, 46.2 to 462 parts by Weight of isopropyl alcohol and 138.8 to 1388 parts by Weight of water; the solution for methyl alcohol comprising, for each 100 parts by weight of the by-product saponied, 81.9 to 819 parts by Weight of methyl alcohol and 153 to 1530 parts by Weight of Water, the saponiied mixture in the water and the alcohol then being extracted with naphtha in a proportion of 1 to 10 parts per part of solution extracted,'then separating the naphtha solution of unsaponiable matter from the Water and alcohol solution of soaps, and evaporating the naphtha to recover the unsaponifiable matter contained therein.

6. A process of obtaining a concentrate of unsaponiable matter of soybean oil, which process comprises the steps of contacting soybean oil containing said unsaponiiiable matter, glycerides of fatty acids of varying degrees of saturation and unsaturation and free fatty acids, with furfural to extract out a fraction of said oil rich in more highly unsaturated glycerides, free fatty acids and unsaponiable matter, contacting the resultant solution with naphtha selectively to clissolve out the major portion of the glycerides from the furfural, evaporating the furfural from the remaining solution of by-product, then -saponifying the free fatty acids and the glycerides of the Toy-product with sodium hydroxide, making up a solution comprising 100 parts by weight upon a water free basis of the resultant mixture comprising soaps of fatty acids of soybean oil and unsaponiiable matter of soybean oil in 146 to 1460 parts by weight of Water and 61 to 610 parts by weight of a monohydric alcohol containing 1 to 3 carbon atoms, then extracting the resultant solution with naphtha in a proportion of 1 to 10 parts by volume per part of solution, separating the naphtha solution of unsaponiable matter from the solution of soaps in water and said alcohol, and evaporating the naphtha to recover the unsaponiable matter contained therein.

7. A process as dened in claim 1 in which the solution of unsaponiable matter in naphtha is Washed with Water prior to the evaporation of the naphtha.

8. A process of obtaining a concentrate of the unsaponiiiable matter of soybean oil from a mixture of fatty glycerides of soybean oil containing from 3 to 50% of unsaponiable matter of soybean oil, which process comprises saponifying the glycerides in said mixture With an alkali making up the resultant mixture containing soaps of free fatty acids and `unsaponiiiable matter into solution with water and a lower monohydric, saturated, alkyl -alcohol containing l to 3 carbon atoms, the solution containing 100 parts by weight upon a Water free basis of the mixture of unsaponiable matter and soaps in 146 to 1,460 parts by weight of Water and 61 to 610 parts by weight of said alcohol, continuously countercurrently extracting the resultant solution with naphtha in a proportion of 1 to 10 parts by volume per part of solution, separating the naphtha solution of saponiable matter contained therein.

9. A process of obtaining a concentrate of the unsaponiable matter of soybean oil from a mixture of fatty glycerides of soy-bean oil containing from 3 to 50% of -unsaponiiiable matter of soybean oil which process comprises saponifying the glycerides ofsaid mixture with anl alkali, acidifying the resultant soapsto liberate free fatty acids, selectively distilling off free fatty acids from the unsaponiable matter, subjecting the still residues to saponiication with alkali in order to convert the free fatty acids therein into soaps, making up the resultant mixture of soaps and unsaponiable matter into a solution comprising parts by Weight upon a .Water free basis of soaps .and unsaponiiiable matter in 146 to 1460 parts by weight of Water and-61 to 610 parts by weight of a monohydric saturated alkyl alcohol containing l to 3 carbon atoms in the molecule, counter-currently extracting the resultant solution with naphtha in a proportion of 1 to 10 parts by volume, per part by volume of solution, separating the naphtha solution of unsaponiable matter from the solution of soaps in water and said alcohol and evaporating the naphtha to recover the unsaponifiable matter contained therein.

10. A process of obtaining a concentrate of the unsaponifiable matter of soybean oil from a mixture comprisingB to 50% by weight of said unsaponifiable matter in soaps of fatty acids of soybean oil, whichprocess comprises making up a solution of 10Q parts by Weight of the resultant mixture of soaps and unsaponiiiable matter in 146 to 1460 parts by weight of water, and 61 to process comprises the steps of treating the soap stock .with alkali to convert the glycerides therein vent to obtain said matter.

2. A process 1V of obtaining the unsaponiable matter of soybean oil saponifiable matter under vacuum, saponifying the free fatty acids in the still residue with alkali, making up the resultant mixture of soaps and l atrasos 19 20 unsaponiable matter into a solution comprising site end thereof a selective solvent of unsaponi 100 parts by Weight upon a water free basis of able matter in a proportion of 1 to 10 parts by the mixture of soaps and unsaponiable matter volume per part by volume of solution, separating in 146 to 1460 parts by weight of water and 61 to the resultant solution of unsaponiable matter 610 parts by Weight of monohydric, saturated in said solvent thereof, at the end of the extracalkyl alcohol containing 1 to 3 carbon atoms, contion zone opposite the end of introduction of the tinuously introducing the resultant solution into solvent of unsaponiable matter and evaporating one extremity of an elongated extraction zone the solvent of unsaponifiable matter from the While continuously introducing solvent of unlatter solution.

saponiable matter which is incompletely soluble l0 15. The process as defined in claim 14 in which in the solution at the other end of the extraction sterols in said unsaponiable matter are then zone, flowing the solution and the solvent counseparated from the remainder of the unsaponiter-currently through each other, removing the fiable matter. solution of solvent and unsaponifiable matter at 16. The process as defined in claim 14 in which the end of the extraction zone opposite to the 15 the sterols are crystallized out from the remainend of introduction of solvent, and evaporating der of the unsaponiable matter.

the solvent to recover the unsaponiable matter 17. In a process of obtaining the sterols of soycontained therein. bean oil from a mixture of acids of soybean oil, l3- A PrOCesS 0f Obtaining unsaponiable matsoybean oil unsaponiable matter and esters of ter 0f sOybean Oil Which PrOCeSS COInpriSeS treat- 20 sterols and fatty acids, the steps of saponifying ine with alkali a concentrate 0f Said unsaponisaid acids and breaking the ester linkages with fiable matter in a material comprising said unalkali, extracting out the free sterols and the sapeniable matter dissOlVed in a prOpOrtiOn Of remainder of the unsaponiable matter from a 3 t0 50% in glyeerides 0f sOybean Oil and a niasolution of soaps of said acids, said unsaponifiable terial 0f a Class Consisting 0f free fatty acids 0f 25 matter and said sterols in water and a lower Soybean Oil and sOalJs 0f said acids Whereby t0 monohydric saturated alkyl alcohol of from 1 to 3 COnVert the glyeerides and free fatty acids inte carbon atoms by means of a solvent of unsaponsOaDs making up the mixture 0f sOabS and Uinfiable matter which is vincompletely soluble in Saponiable matter in a proportion of 100 parts the solution and separating the sterols from the by weight upon a Water free basis into solution remainder of the unsaponiable matter.

in Water in a prODOrtiOn 0f 146 t0 1460 parts by 18. In a process of obtaining unsaponifiable Weight and a lOWer mOnOhydriC Saturated alkyl matter of soybean oil in high concentration from alCOhOl Containing 1 t0 3 CarbOn atOInS in a prO- a mixture of soaps of soybean acids and said unportion of 61 to 610 parts by Weight, feeding the Sapomable matter obtained by saponication resultant solution continuously into one end of with alkali, a, material containing 3 to 50% by an elongated extraction zone, feeding intO the weight of said unsaponiable matter in a mixture same Zone at the OpDOSite end thereOf, a SOlVent of glycerides of soybean oil and a material of a of unsaponifiable matter insoluble in the solution class consisting of soybean fatty acids and soaps in a PrODOrtiOn 0f 1 t0 10 Darts by Volume Der of said acids, said first mentioned mixture being Dart by VOlume 0f the sOlutiOn, drawing Oil the 40 dissolved in a solvent solution containing, for

solution of unsaponiable matter in said solvent each 100 parts by weight upon a Water free basis at vthe end of the extraction Zone Opposite the oi said iirst mentioned mixture, 146 to 146o parts end of introduction of the solvent, and evaporatby Weight, of water, and 61 to 61o parts by weight ing the solvent to recover the unsaponiable matof a monohydrlc alkyl alcohol containing 1 to 3 ter Centailed thereincarbon atoms per molecule; the steps of feed- 14- In a prOCeSS 0f Obtaining unsapOnifiable ing the solution into an elongated extraction zone matter of soybean oil in high concentration, the at one end thereuf, feeding into the Same Zone steps which comprise saponifying the glyerides at the opposite end thereof, a selective solvent of of Soybean oil in a mixture Containing unsaponiunsaponiabie matter in a proportion oi i to 1o fiable matter of soybean oil in a proportion of parl-,S by volume per part by volume of solution of 3 t0 50% in said glycerdes and a material 0f a said first mentioned mixture, removing the rcclass consisting of free fatty acids of soybean oil Sull-,ant 50ml-,lon of unsapomable matter in said and Soaps 0f Sad acids treating the resultant solvent thereof at the end of the extraction zone mixture of Soaps and unsaponiable matter with opposite the end of introduction of said solvent acid. t0 liberate the free acids and t0 OI'm 55 and evaporatng Said Solvent from latter Solusoluble salts of alkali, washing out the soluble tion to obtain Saud unsaponmable matter Salts a; Solvent thereof in the 19 The Steps as dened claxm acids and unsaponable matter' dlstumg Off a the solvent of unsaponifiable matter is naphtha. substantial amount of the free fatty acids under 20, The process of claim 10, in which the naph.. vacuum to obtain a still residue rich in unsaponitha, employed in continuously counrepcurrerrtly fiable matter, resaponifying the fatty acids re' extracting the solution of soaps and unsaponimanng in the Stm residue with alkali' making fiable matter in water and monohydric alcohol, up the resultant mixture 0f Soaps of fatty acids contains added monohydric alcohol in an amount and unsaponifiable matter into a solution comto inhibit emulscaton difficulties. prising 100 parts by weight upon a water free 65 basis of Said lil'ue' 14%)50 14260 sans byheht References Cited in the file of this patent, of water, an o 61 par s y weig o a monohydric, saturated alkyl alcohol containing 1 UNITED STATES PATENTS to 3 carbon atoms, feeding the resultant solution Number Name Date into an elongated extraction zone at one end 2,173,629 Milas Sept. 19,1939

thereof, feeding into the same zone at the oppo- 

1. A PROCESS OF OBTAINING A CONCENTRATE OF THE UNSAPONIFIABLE MATTER OF SOYBEAN OIL FROM A MIXTURE OF FATTY GLYCERIDES OF SOYBEAN OIL CONTAINING FROM 4 TO 30% OF UNSAPONIFIABLE MATTER OF SOYBEAN OIL AND 5 TO 40% OF FREE FATTY ACIDS OF SOYBEAN OIL, WHICH PROCESS COMPRISES SAPONIFYING THE GLYCERIDES AND THE FREE FATTY ACIDS IN SAID MIXTURE WITH AN ALKALI, MAKING UP THE RESULTANT MIXTURE CONTAINING SOAPS OF FREE FATTY ACIDS AND UNSAPONIFIABLE MATTER INTO SOLUTION WITH WATER AND ISOPROPYL ALCOHOL, THE WATER BEING PRESENT IN A PROPORTION OF 277.5 TO 2775 PARTS, AND THE ISOPROPYL ALCOHOL BEING PRESENT IN A PROPORTION OF 92.5 TO 925 PARTS FOR EACH 200 PARTS OF THE MIXTURE, THEN REMOVING THE UNSAPONIFIABLE MATTER FROM THE MIXTURE BY INTRODUCING THE SOLUTION INTO THE UPPER PORTION OF AN EXTRACTION ZONE WHILE INTRODUCING NAPHTHA, IN A PROPORTION OF 1 TO 10 PARTS PER PART OF SOLUTION, INTO THE LOWER PORTION OF THE SAME ZONE, DRAWING OFF THE NAPHTHA SOLUTION OF UNSAPONIFIABLE MATTER AT THE TOP OF THE ZONE, AND EVAPORATING THE NAPHTHA TO OBTAIN SAID FRACTION OF UNSAPONIFIABLE MATTER. 